Exhaust vents or traps are well-known and commonly seen on exterior walls of buildings such as houses. They generally consist of a plate fixed to a side wall of a building and connected to an exhaust duct, and a flapper or damper hinged at the top of the plate. The exhaust duct is generally connected to a laundry dryer, a bathroom ventilator, a stove ventilator, and the like. Air exits the exhaust duct under the pressure produced by a fan or a blower, opening the flap or damper. When no air exits the duct, the flap lies against the plate in a closed position. In other types of exhaust vents, louvers or laths may be used instead of a single flapper.
Examples of known exhaust vents can be found in U.S. Pat. No. 3,682,084 to Tarnoff, U.S. Pat. No. 3,584,566 to McCabe, U.S. Pat. No. 6,772,538 to Vagedes, U.S. Pat. No. 6,974,379 to Koessler, U.S. Pat. No. 5,046,408 to Eugenio, as well as in US patent application no. 2009/0114413 to Daviau.
One of the major problems with existing exhaust vents provided with a hinged flapper or damper is that even when they are in a closed position, small apertures or gaps remain at the interface of the flapper and the plate, and air infiltration from the outside to the inside of the building can occur. This situation is particularly problematic in colder regions, where cold air from the outside enters the building or the house through these infiltration apertures.
Conversely, in warmer regions, or during warmer seasons, buildings and houses are often air-conditioned, and hot air from the outside often enters the house through these infiltration apertures. Furthermore, air that has been air-conditioned can also exit the houses or buildings through these exhaust vents even when the exhaust system is not in use, due to the fact that the flapper of the exhaust vent is not properly closed over the plate.
Another drawback of existing exhaust vents is the fact that an accumulation of snow near the exhaust vent can prevent the flapper or damper from opening properly, preventing air from exiting the exhaust duct. Conversely, high winds may also cause the flap of existing exhaust vents to open, thereby contributing to the above-described undesirable heat transfer.
In view of the above, there is a need for an improved exhaust which, by virtue of its design and components, would be able to overcome or at least minimize some of the above-discussed prior art concerns.